First three. A, b, c.
The triangle is a right triangle.
The triangle is a Pythagorean triple.
The triangles hypotenuse is 39 inches.
Answer:

⇒
[Factorized form]
Step-by-step explanation:
Given expression:

We need to make
the subject.
In order to do that we need to solve the expression for
in terms of
and 
We have,

Subtracting both sides by 


Taking square root both sides in order to remove square of 


The difference of squares can be factorized and written as:
[difference of squares
]
Answer:
16 degrees
Step-by-step explanation:
<u><em>The question is</em></u>
Find the measure of angle R
we know that
An exterior angle of a triangle is equal to the sum of the opposite interior angles
so
In this problem

we have

substitute


18 +6x = 48
6x= 48-18
6x=30
X= 30\6
X=5